Great tits: still murderous, rapacious, flesh-rending predators!

Thanks to Ville Sinkkonen, I've just learnt of this Finnish news article: it reports wildlife photographer Lassi Kujala's discovery of more than ten Common redpolls Carduelis flammea killed by Great tits Parus major. A Yellowhammer Emberiza citrinella was killed as well. I understand that tits are called titmice in some parts of the world. So, seriously, would you call this species the 'Great titmouse'? Well, I'm sticking with tits, thank you very much. Tits all the way.

Anyway, the (brief) article explains how this is an astonishing discovery, representing something remarkable that might be a first. I don't want to downplay the achievements of a passerine that's capable of killing numerous redpolls (and it isn't clear whether we're seeing the behaviour of a single individual, a set of individuals acting alone, or a co-operating social group [UPDATE: the killings apparently represent the actitivies of two or three Great tits]), but let's note that this sort of thing (that is, the killing and eating of other passerines by the Great tit) is actually not in the least bit novel, nor unusual, for this species.

Great tit, photographed in Czech Republic. Image in public domain.

Great tits mostly feed on insects and seeds. In fact, during the winter, about 90% of the northern European Great tit diet consists of plant material*. It's powerful and formidable for its size, able to use its bill to break into hazelnuts and acorns. It’s also an accomplished raider of caches created by other passerines, in particular those of the smaller Marsh tit Poecile palustris and Coal tit Periparus ater**; unlike these species, the Great tit does not [in general] hoard food. It's also a facultative tool-user, reported on occasion to use conifer needles to winkle insect larvae out of bark (Gosler 1993). And it’s also a part-time scavenger, its habit of picking at the bones of hoofed mammals being well known (e.g., Selva et al. 2005). Even better, historical records tell of them eating the fat and other tissues of hanged people. I was reading about this just the other day but can no longer remember which book it was in...

* As is the case with so many ‘European’ birds, the Great tit has a huge range that encompasses much of Asia as well as northern Africa. It inhabits tropical woodland and forest as well as the habitats of the cool north.

** You’ll note that I’m using the new taxonomy for tits. Parus of tradition warrants splitting up (due to deep genetic divergences and a lot of disparity) and is also paraphyletic, given the discovery that Pseudopodoces is deeply nested within it.

Rather less well known is that the Great tit sometimes uses its relatively large size and powerful bill to kill smaller passerines, and indeed Barnes (1975) noted that “A topic of some interest to earlier writers was the alleged murderous tendency of great tits” (p. 112). While some of the accounts I'm discussing here do involve predation on other species, note that others involve competition for nesting sites. Barnes described two or three cases where Pied flycatchers Ficedula hypoleuca were “found dead with smashed skulls in nest-boxes taken over by great tits” (p. 112), and also referred to occasions when Great tits had attacked and killed birds that were caught in traps, nets or cages. Caris (1958) reported a case in which an English Great tit was seen flying away with a dead Goldcrest Regulus regulus (one of Europe’s smallest passerines: it may weigh just 5g). It had been killed by a peck to the back of the head. Its eyes were pecked out and its skull mangled.

Even better, Howard Saunders (1899) wrote that “The Great Titmouse will attack small and weakly birds, splitting their skulls with its powerful beak in order to get at their brains; and it has even been known to serve a Bat in this manner”.

In recent years, the killing and eating of bats by this species became internationally known after Estók et al. (2010) published a paper on the subject in Biology Letters. They reported how the tits were finding hibernating bats in cavities in caves, bashing the bat's heads in, and eating them... or, rather, eating their brains. It was excellent that Estók et al. (2010) were able to document (and photograph) this in such detail, but bat-killing isn't a newly discovered bit of behaviour. And if you know your recently published zoology books you may perceive the link between the brain-eating behaviour of Great tits and the title of a recently published and reportedly excellent book. In fact, the text you've just read is mostly recycled from a Tet Zoo ver 2 article published back in 2009. If we look at the comments there... hmm, is this, perchance, the genesis of the Zombie Tit Meme? I don't know, since I haven't yet seen the book concerned: Becky Crew's Zombie Tits, Astronaut Fish, and Other Weird Animals (2012, New South Books).

Great tit interacting aggressively with a Blue tit (Cyanistes caeruleus) - not a predatory interaction, however. Image by Ville Sinkkonen.

While I'm here, some announcements. I've recently launched a site - darrennaish.wordpress.com - that serves as a repository for most (that is, as many as I have) of my publications. Do check it out. And John Conway and I recently launched the Tetrapod Zoology Podcast. Ep 1 - an experimental prequel - is now available, and we're making this a regular thing. Tune in for Tet Zoo-themed discussion, shout-outs and general nonsense.

Back to tits. They're actually of controversial position within the passerine radiation, seemingly not grouping within any of the four major clades within Passerida. For more on that and other passerine-themed issues at Tet Zoo, see...

Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com!
Follow on Twitter @TetZoo

The views expressed are those of the author and are not necessarily those of Scientific American.

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